Rotating jet device for airfoils



' July 26, 1949. J. G. LEE 2 7 461 ROTATING JET DEVICE FOR AIRFOILS Filed July 29, 1945 I INVENTO' Jo%% 611199 WXM,

Patented July 26,1949

ZATZAGE STA ES U w 2,477,461 1 "jf goTATING JET DEVICE FOR AIRFQIPSW John G. Lee, Farmington, Conn, assignor to 'rUm'ted Aircraft Corporation, East Hartford,

euimeteir v of jone type-of, d l

m felates toanapparatus and a method for redu rig 'r'ic'reasingthe effect of the tip vortices created by an airfoil having a velocity relettiv'e tcj "aIi'tream passing there- Fig: 1 is a {partial plan -v partly in section, showing in schematic form a right hand portion of an aircraft having an airfoil whose tip section is 7 provided pith... means, for. pr

Z'i v i le 1... alongthe line 2*: I Fig. 1 Fig. 3is aperspective view,

partly in section,

partlybroken away, ior" producing a rotating ws owing the effect e .eneir e amen .letlidtafi s bo an axisfltransvers tothedii'ection of movement of th tirs ea ela ive t hei tm tic pe pective viewjof vortices ing overthe tip por- 9. .5

having ro 1 9 weirdly (as in Fig. 1)

i faee a e H howin e wat -192. 39. .whi hjs idiets a d fiected bygthe airstre 'm; and infwhich. they tend torotate the air'st sing ov er the airfoil p-:0'.".;j' Q

.pFigqjl is a.view similar toglifig fi, but with the jetsj increasedia number and positioned forwardlyoft ieilea ine e eeioitbeairf il- .F e-.8.1 ja cu away. mer t e ew of modification of the rctati g jet forming device.

Elie. is airl ni wine tip t o h v n anozzle arranged thlargega rearwardly directed fluid jet which rotatesflabout its own axis.

1 F Conn., a corporation of Delaware Application July 29, 1943, Serial No. 49 .553

1 9 Claims. (01. 244-40) drag, or resistanceto the motion of the airfoil over. i l relative tojtheaih'f .Anobiect ofl'this invention is to provide alight According 'tothis invention, rapidly rotating Weight and lficient means utilizing a rotating fluid jets; which may in jsome instances have a fluid jet for aiding: 'or opposing the tendency of peripheral rotational velocity of ."several times the 1. an airstreami passingebveruthe tip portion of an velocity of the airstreamfrelative to the airfoil, airfoil towhirlvor. rota-teat r i 10 are projected outwardlyjronnan airfoil'into the 9 th j i dyantageswill be ppa en airstream flowing thereover. in amahner to either r th s ec fieeiio iam from the reduce or increase"(depending upon the direction accompanyin draw n w c illustrates What of rotation and direction of projection of fluid Qbe-awp fe d embodiment. jets) the induced-drag 'ahdother effects caused by the creation ofjjtiplvortices in theairstream passing overthe airfoiL.

i such as an aileron I8. Wing 16 is formed to provide a pressureduct 22 preferably within its leading edge, the walls of this duct bein constituted by e wi g su tac saditqen thei dmg edge. to and a supporting spar=34 extending spanwise of the wing. The outboard freeiend vor tip of the wing is formed asaiclosed pressure chamber 253 bounded by lower wing surface-t6, upper wing surface 38, leadingedge 41!, trailing edge 42,. and a chorclwise extendin rib 32. Rib or wall 32 has an opening 21 thereinjthrough which fluid under pressureis passed fromiductlllz to chamber 29.

Within chamber are. af'plurality of whirler nozzles, in this instaric'ethree nozzles 24, 2e and Two ofthese nozzles -(24 and in Fig. 1) are formed with a convergingiconica-l portion (Fig. 3) having a discharge opening (25, in Fig. 1) at the small end thereof and closed at the other end by a wallE l. Atthe larger diameter end of converging nozzle 5!! area circumferential series of curved vanes or blades 52;between which are passages 53 each convergingirom a large inlet, open to the chamber side of the nozzle, to a small Fie. 1:0. i 1 .se e ng h n l wof discharge e n iiq i i oih interior of the Fig. 9. T f, nozzle. e

u walon g thelinell-all 50 The thirdnozzlatll may be formed (Fig. 8) of Fig.9. r 9 simply as a convergingpassage. having a spiral It is knownthat a whirl or vortex is caused by he..fl@ .;oif a gto' pressure r i ns adia enmh tip Por on 9i n i i such as awlng, rotorb1ade;'or propeller, when the baffle 54 therein which gradually increases in twist or decreases in pitch iromthe inlet opening 51 to the discharge opening 59;jWhile thenozzles shown are converging only, converging-diverging I aircraft propelling engine.

: to. t ans nic;.re...

Venturi nozzles may be instances.

A fluid under pressure, such as compressed air from a compressor (not shown) within the fuselage ll], or a mixture of compressed air and engine exhaust gas, is forced through the duct 22 to the chamber 20. Various sources of pressure fluid may be used within the scope of this invention to supply the chamber 20 and the nozzles which discharge jets therefrom and therefore no specific source of pressure fluid has been shown. However, it is preferred that the fluid be compressed atmospheric air, which may be engine cooling air preferable in some mixed with the products of combustion from the Such fluid contains energy in the form of heat from the engine, which may be at least partially utilized in forming the rotating fluid jets of this invention. By leading the compressed fluid, which is heated by the proc ess of compression or by the introduction of hot engine exhaust gas thereinto, through the interior of the leadin edge portion of. the wing the heat from the fluid may also be utilized to de ice the wing, or airfoil, through which it passes.

The pressure of the fluid within chamber is maintained higher than the pressure of the air surrounding the wing and consequently the pressure fluid within chamber 20 will flow through the nozzles 24, 26, and 30 to the lower pressure area surrounding the exterior of theairfoil. As the pressure fluidj passes through the nozzles a portion of its pressure energy is changed to velocity, and it issues from the discharge openings 25, 21!, iii in the form of a jet having a high velocity. The jet is also given a rotative velocity component, or whirl, as it passes through the vanes 52 or the initial flights of spiral baffle 54. This velocity of rotation about the axis of the nozzle or jet imparts an angular momentum to the fluid which, as thecross-sectional area of the stream decreases, results in a continually increasing velo-cityof rotation of the jet as it passes through the converging nozzle, Thus the jets issuing from the discharge openings 25, 21, and 3i rapidly whirl or rotate about their own axes, as shown at A in Fig. 3. The velocity of each jet both around and along its axis may be varied by varying the pressure of the fluid in chamber 20 in relation to the pressure of the airstream passing over the chamber. Forinstance, this might be done by a throttle valve 61 in duct 22 of Fig. 1. The position of throttle 67 may be varied by shifting rod 69 attached to the throttle by'arm 68, thus providing a control for varying the effect of or for selectively applying the jets; By varying the design or the angle of vanes 52 the rotative velocity component of the jet A may be varied in relation to the linear velocity thereof. vanes 52 may be made adjust: able, as by pivoting them at a point intermediate their length, for changing their position so as to vary the direction of passages 53; relative to the axis of the nozzle and consequently the rotative component of jets A, whilethe aircraft is in flight. In Fig. 3, pivoted vanes 52 may be adjusted so as to alter the rotative velocity of jet A by shifting rod 55 so asto turn gear 6L As gear 6| is rotated,

the pinion gears 63 meshing therewith and carlimited to the specif c ev 5,135??? d sulting velocity of the mainstream will be greater on one side of the jet and less on the other side thereof. This will cause a relative pressure difference between the two sides of the rotatingjet, which is called the Magnus effect, and which will create a force tending to move the jet transversely of the airstream, as indicated by the arrow R. in Fig. 4, toward the side having the higher resulting velocity.

Thus, when the whirlers or nozzles 24, 26 and 30 are arranged to rotate the jets issuing therefrom about their own axes, in the directions shown in Fig. 6, the airstream passing over the Wing will tend to deflect the jets, and a portion of the airstream therewith, circularly or spirally in a manner to counteract or'oppose the tip vortex normally present in an airstream passing over a wing tip as shown in Fig. 5. The whirling or revolving jets of this invention may therefore be used to oppose the formation or decrease the magnitude of tip vortices and thereby eliminate or reduce the deleterious effects thereof.

Conversely, if the nozzles are adjusted (Fig. 3) to rotate and revolve the jets in directions respectively opposite to those shown in Fig. 6, the jets and. a portion of the airstream carried therewith will be deflected'in the same direction as the tip vortex as shown inFig. 5, and will therefore tend to augment same. By such means the magnitude of the tip vortices may be increased, and the whirling jets may therefore be used as a means to increase the drag of the aircraft, or as an aerodynamic brake. r 1

The wing tip may be provided with a forwardly projecting portion from which the rotating jets are discharged into the airstream. Four such jets are shown discharging from the projection 66 in Fig. 7.

Backwardly or forwardly pointing jets, rotating about an axis extending generally in the direction of the axis of the-normal'tip vortex, may also be used. Thus, in Figs. 9, l0, and 11, a nozzle "lil preferably tapered, is arranged to discharge a fluid jet backwardly relative to the motion of the airstream over airfoil l6. Fluid under pressure is supplied to nozzle 10 by a duct 1| and a tapering passage "which opens tangentially. at 14 into the larger diameter end of nozzle 10. The angular momentum imparted to the fluid stream as it enters nozzle 10 tangentially results in a continuous increase in rotational velocity of the fluid as it passes through the tapering nozzle, from which it issues as a fluid jet having a linear velocity relative to the airfoil l6 along an axis extending generally in the di ection of motion of the airfoil relative to the airstream and having a rotational velocity about said axis. The angular momentum imparted to the jet may (as in Figs. 10, 11) be in a direction to revolve the jet to oppose the rotation of the tip vortex, to decrease its effect; or the jet may revolve in the same direction as the tip vortex, so as. to increase'its effect. Adjustable means for controlling the velocity and direction of jet rotation, such as shown in Fig. 3, may be also used in connection with the modification of Figs. 9, 10, and 11.

As ref-erred'to herein theword revolve differs from the word rotate and is used to indicatemovement about a center as denoting for example that the earth rotates on its axis and revolves about the sun.

It is to be understood, thatthe invention is not bod 'erei'n illus- Ways without deparature from its spirit as defined by the following claims.

I claim:

1. In an aircraft, a lift producing airfoil having a source of fluid pressure therein, and means for controlling the drag caused by the flow of air around the tip from beneath said airfoil to the low pressure area above the airfoil including a nozzle carried by said tip receiving fluid from said source and discharging externally of said airfoil and baflie means in the fluid stream passing through said nozzle for imparting a revolving movement to the jet issuing from said nozzle.

2. In an aircraft, a wing having a tip portion, a source of fluid pressure therein, and means for reducing the drag caused by the trailing wing tip vortex including a wing tip nozzle receiving fluid from said source and discharging said fluid as a jet directed transversely to the direction of the air stream passing over said tip portion and battle means in the fluid stream passing through said nozzle for imparting a rotary movement to the fluid within said jet whereby aerodynamic forces act on said jet to bodily gyrate the jet in opposition to said wing tip vortex.

3. In an aircraft, a wing having a tip portion,

a source of fluid pressure therein, and means for reducing the drag caused by the natural wing tip vortex including a plurality of nozzles communicating with said pressure source and discharging externally of said wing and transversely to the direction of the airstream passing over said tip portion and means in the fluid stream passing through said nozzles for imparting rotational movement to the fluid whereby aerodynamic forces act thereon to induce a vortex movement to the jets issuing from said nozzles, said nozzles being disposed adjacent said wing tip portion so that the vortex movement of the jets opposes said wing tip vortex.

4. In an aircraft, a Wing having a wing tip chamber, means for introducing fluid under pressure into said chamber, and means for controlling the drag caused by the flow of air around the wing tip from beneath the wing to the low pressure area above the latter including a nozzle carried by the upper surface of the wing tip, said nozzle receiving fluid from said chamber and discharging upwardly from said wing tip surface and baflie means acting on the fluid stream discharged from said chamber for imparting a revolving movement to the jet issuing from said nozzle, and means for controlling said bafile means to reverse the direction of revolving movement of said jet about the nozzle axis.

5. In an aircraft, a wing, a tip portion having a chamber therein, a projection extending forwardly of the leading edge of said tip portion, means for introducing a fluid under pressure into said chamber, means for controlling the drag caused by the natural vortex trailing from said wing tip including wing tip nozzles receiving fluid from said chamber and located on the upper and lower surfaces of said projection and discharging said fluid as jets above and below said surfaces in directions substantially normal to the direction of the air flowing past said wing and baflle means for imparting revolving movement to said jets issuing from said nozzles, and manually operative means for controlling said baille means to effect opposite revolving movement of the fluid in said jets.

6. In an aircraft, a wing having a source of fluid pressure therein, means for controlling the drag caused by the vortex trailing from said wing tip including wing tip nozzles receiving fluid from said source and located on the upper and lower surfaces of said wing and discharging above and below said surfaces substantially normal to the direction of the air flowing past said wing and baflle means for imparting rotary movement to the jets issuing from said nozzles and arranged to effect opposite revolving movement of said jets about the axes of said nozzles, and manually operable means for reversing the pitch of said bafiles to reverse the revolving movement of said jets about said nozzle axes.

7. In an aircraft, a wing having a source of fluid pressure therein, and means for controlling the drag caused by the flow of air around the wing tip from beneath the wing to the low pressure area above the latter including a wing tip nozzle receiving fluid from said source and discharging said fluid as a jet laterally from said wing tip and baiile means for imparting revolving movement to said jet issuing from said nozzle.

8. In an aircraft, a wing having a source of fluid pressure therein, and means for controlling the drag caused by the natural vortex movement of air flowing around the wing tip from beneath the wing to the low pressure area above the latter including a wing tip nozzle receiving fluid from said source and discharging said fluid as a jet rearwardly from the trailing edge of said wing and baflie means between said pressure source and the discharge end of said nozzle for imparting a revolving movement to the jet is- .suing therefrom in'opposition to said natural vortex movement.

9. In an apparatus for controlling the natural vortex in an air stream passing over the tip portion of an airfoil, a source of fluid under pressure, a nozzle communicating with said pressure source and discharging fluid as a jet into said air stream in a direction substantially normal to the direction of the air stream flowing past said tip portion, and means to produce a deflection of said jet and a portion of said air stream in a predetermined direction relative to the direction of rotation of said natural vortex including bafile means for imparting a revolving movement to said jet about its own axis.

JOHN G. LEE.

REFERENCES CITED The following referenices are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,493,753 Koleroff May 13, 1924 1,580,577 Baumann Apr. 13, 1926 2,048,847 Desmet July 28, 1936 2,075,817 Loerke Apr. 6, 1937 FOREIGN PATENTS Number Country Date 448,116 Germany Apr. 14, 1927 

